PHP: can't send arabic characters to twitter

i use this to update status on twitter http://tutorialswalk.info/demo/twitter-update-php-oauth/

you can download it from the tutorial link

but when i type in a开发者_高级运维rabic "مرحباً" it not update the status, what is the problem?

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Did you try to encode it to UTF8?
I am sending hebrew characters with no problem.
http://il2.php.net/manual/en/function.iconv.php